Because people remember things differently. They might remember different parts of the event.
Political system of the Chinese
The arctic ocean is the smallest ocean in the world.
Answer
If the scale is a verbal statement (i.e. "1 inch equals 1 mile"), determine the distance by simply measuring it with a ruler. For example, if the scale says 1 inch = 1 mile, then for every inch between the two points on the map, the real distance on the ground is that number in miles